Funding of this application will establish a Clinical Center for the "Clinical Trial of Medical Therapy in Benign Prostatic Hyperplasia", a multi-center trial sponsored by the national Institute of Diabetes and Digestive and Kidney Diseases at the Clinical Trials Center, University of California, San Diego (UCSD). The primary objective of the trial is to ascertain if medical therapy (finasteride and/or doxazosin) delays or prevents the progression of BPH. If selected as a clinical center, the UCSD Clinical Trials Center will recruit, screen and enter for evaluation 240 suitable subjects into the study over a two year enrollment period, and complete the study following the standardized multi-center protocol.